Cloud parameters as a function of geometrical cloud radius ﹩r_{A}﹩ for cloud G, which is associated with NGC 7538 (top panels) and cloud D, toward Cas A (bottom panels). Filled symbols represent results from CO, open symbols those from ﹩^{13}﹩CO. (a) CO luminosity integrated over velocity and solid angle, ﹩S_{12}﹩ and ﹩S_{13}﹩, and the ratio ﹩S_{12}/ S_{13}﹩. (b) Intensity‐weighted measures of cloud size; for comparison, the dashed line shows the relation ﹩y=x﹩. (c): Cloud mass from CO and ﹩^{13}﹩CO luminosity, ﹩M_{\mathrm{CO}\,}﹩ and ﹩M_{13}﹩, and virial mass, ﹩M_{\mathrm{vir}\,}﹩.